1. Fields of the Invention
The present invention relates to a passive anode gas recovery system for fuel cells, especially to a passive fuel recovery system arranged at an outlet end of an anode of a fuel cell that recovers unconsumed hydrogen gas in the fuel cell for recycling and reuse. The passive fuel recovery system of the fuel cell has high efficiency and low cost.
2. Descriptions of Related Art
In order to provide current the load required, hydrogen gas more than the anode of fuel cells required is supplied. Thus a part of hydrogen gas unconsumed needs to be exhausted. However, once being exhausted to the atmosphere, there is a risk of explosion due to combustion reaction of the hydrogen gas. Thus the residual hydrogen gas must be recovered during operation of the fuel cell. In most of the fuel cells available now, active devices such as pumps are added for recycling of the hydrogen gas. Yet the pump added consumes more power. An extra controller is required for the system. This causes increasing of the cost and the volume of the system is larger. In order to solve the problem mentioned above, some research uses certain structure such as ejectors for hydrogen recovery of fuel cells. The two ejectors are connected to form a large-scale ejector for recycling and reuse of hydrogen gas not reacted. Yet the recovery efficiency is low due to insufficient vacuum in the ejector caused by the larger air chamber in the ejector. In order to overcome these shortcomings, there is a need to provide a novel recovery system for fuel cells with advantages of compact volume, light weight and low cost.